Rudder or keel for a wind and/or power propelled vessel

ABSTRACT

A rudder or keel for a wind and/or power propelled vessel, the keel or rudder having at its rear part mounted thereon at least one extension blade which is adapted, from the hull of the vessel, to be rearwardly extended from or retracted to a position wherein its rear edge substantially does not project rearwardly of the trailing edge of the keel or rudder. This will enhance the maneuverability and rudder movement, or increase the required keel lift by reducing leeway and/or improving the trim.

[ 1 Sept. 12, 1972 [54] RUDDER OR KEEL FOR A WIND AND/OR POWER PROPELLEDVESSEL [72] Inventor: Ericus Gerhardus Van de Stadt,

Beemster, Netherlands [73] Assignee: Van de Stadt, E.G. Scheepwert N.V.,

Zaandam, Netherlands 22 Filed: April 15,1971

21 Appl. No.: 134,322

52 us. 01 ..114/152 51 1111.01. ..B63l1'25/44 58 Field 61 Search..114/162, 144, 145,152, 164, 114/167 [56] References CitedUNI'I'EDSTA'IESPATENTS 3,001,502 9/1961 Stoker ..114/167 PrimaryExaminer-Andrew H. Farrell Attorney-Waters, Roditi, Schwartz & Nissen[57] ABSTRACT A rudder or keel for a wind and/or power propelled vessel,the keel or rudder having at its rear part mounted thereon at least oneextension blade which is adapted, from the hull of the vessel, to berearwardly extended from or retracted to a position wherein its rearedge substantially does not project rearwardly of the trailing edge ofthe keel or rudder. This will enhance the maneuverability and ruddermovement, or increase the required keel lift by reducing leeway and/orimproving the trim.

7 Claims, 3 Drawing Figures,

PATENTEBsEP 12 m2 sum 1 or 3 7 A TI l 7- 1 11 z i w 2 7 RUDDER R KEELFOR A WIND AND/0R POWER PROPELLED VESSEL The invention relates to arudder or keel for a wind and/or power propelled vessel.

It is known that under certain conditions such as for instance whenmanoeuvering in narrow fairways or in the case of sailing vesselsrequiring excessive weather helm when sailing large or before the windthe need may be temporarily felt for a, greater manoeuvrability orrudder moment than can be'obtained with the existing rudder. Similarly,circumstances may arise under which it is desirable, in order to reduceleeway and/or to improve the trim, to increase the transverse force orlift provided by the keel by increasing the area of the latter.

According to the invention the above. desiderata are met by the rudderor keel at its rear part having mounted thereon at least one extensionblade which is adapted, from the hull of the vessel, to be rearwardlyextended from and retracted to a position wherein its rear edgesubstantially does not project rearwardly of the trailing edge of therudder or keel. I

In a rudder or keel in the form of a hollow body with asymmetricallystreamlined cross-section, according to a preferential embodiment of theinvention, both sides of the hollow body have provided thereon anextension blade which which in its retracted position closely seats onthe outer surface of the said body. Thus, extension of one of the saidblades produces a asymmetrical wing section which, in accordance withthe laws of hydrodynamics, upon movement ofthe body through the water inthe direction of the chord creates a transverse component towards theside having the largest curved area, which component in the case of asailing vessel can be utilized, by extending the leeward blade, to causethe incidental effect obtained by said wing section to exercise itsinfluence in the desired direction.

' Further characteristics and advantages of the invention will becomeapparent from the following description of a preferential embodiment ofa rudder constructed in accordance with the invention with reference tothe drawings.

FIG. 1 shows a cross-section along the line 1-1 in FIG. 2 on a largerscale;

FIG. 2 shows a horizontal cross-section along the line II-H in FIG. 1 ona larger scale;

FIG. 3 shows a fragmentary section along the line III-III in FIG. 2 on astill larger scale.

The balanced rudder for a sailing vessel which has been chosen forpurposes of illustration of the invention comprises a hollow body 1which is streamlined in cross-section, its greatest thickness beingforward of the middle. In the rearrnost portion of this streamlinedrudder body, against both lateral faces thereof, a blade 2 which extendsalong its entire hight is mounted for longitudinal sliding movement. Theinner side of these blades has a curvature which corresponds with thatof the concerning lateral face of the rudder body 1 while the curvatureof their outer side is slightly greater so that the blades 2 tapertowards their front and rear end and therefore do not appreciablyinterfere with the smooth contour of the concerning lateral face of therudder body irrespective of their position thereon.

In the chosen example the longitudinal dimension of the blades 2slightly exceeds half the longitudinal dimension of the rudder body 1.Approximately at a distance from their leading edge which correspondswith a quarter of their longitudinal dimension each of the blades 2carries at its inner side two vertically spaced brackets 3 which areboth guided in a longitudinal slot 4 in the wall of the hollow rudderbody 1, the

. location and length of the longitudinal slots 4 being such that theblades 2 in their foremost or retracted position have their trailingedge in alignment or flush with the trailing edge of the rudder body andin their rearmost or extended position project rearwardly of the rudderbody 1 by approximately half their width.

At their end which lies inside the cavity of the rudder body the twobrackets 3 of each rudder extension blade 2 each carry a pinion 5 which,for a purpose explained below, is secured to a vertical rotary shaft 6common to both pinions 5 which is supported in both brackets. Thepinions 5 each mesh with a toothed rack 7 secured to the inner side ofthe concerning wall adjacent the guiding'slot 4 and apart frommaintaining the blades against the outer side of the rudderbody 1throughout the ex tent of their displacement with regard thereto alsoserve to transmit a displacing force from one of the brackets 3 to theother bracket by means of the common rotary shaft 6 so that the bladescannot take up an oblique position and jam.

In the illustrated embodiment displacement of the blades 2 with regardto the rudder body 1 through the distance permitted by the guiding slots4 occurs by means of a hydraulic control system. This system comprisesfor each blade 2 a hydraulic ram 8 of which the piston rod 9 acts on oneof the brackets 3 of the concerning blade 2. As shown in the drawingboth hydraulic rams 8 are disposed in the lower part of the hollowrudder body 1 for cooperation with the lower brackets 3 in order not toform an obstruction for the rudder stock which must have its greateststrength in its upper part. In order to make allowance for thecircumstance that in view of the interior shape-of the hollow rudderbody 1 the path of movement of the points of application of the pistonrods 9 with the brackets 3 is inclined with regard to the longitudinalcenter plane of the hollow rudder body 1 the hydraulic rams 8 and thepiston rods 9 are each hinged to the rudder body 1 and to the bladebrackets 3 respectively about a vertical spindle.

The hydraulic lines l0, ll, 12 extend upwardly along the rudder stock 13and through the helm port socket 14.

It will be understood that a hollow keel body for a sailing vessel canbe arranged in a completely corresponding manner and that in view of theconverging lateral faces of the rudder or keel body only one of the twoblades 2 can be extended at a time.

In the case of a rudder the extension of the blades 2 will result in anincreased steering capacity but in view of the asymmetrical wing sectionobtained thereby such increase of the steering capacity will be greatestto port and to starboard when using the starboard or port extensionblade respectively. By for instance, in the case of excessive weatherhelm to starboard, extending the port side rudder extension blade 2 moreor less according to the degree of weather helm to starboard the rudderdeflection which is otherwise necessary to compensate for the weatherhelm but is detrimental to the speed of the vessel can be reduced to asmaller value.

Although in the case of a keel the end. in view is primarily a decreaseof the drift and the drift angel rather than an increase of the steeringcapacity, similar considerations apply. By more or less extending theleeward keel extension blade the asymmetrical wing section of the keelbody produced thereby will create a larger or smaller transversepressure component in the leeward direction which will decrease thedrift angle, whereby the vessel, for instance by sailing closer to thewind, will have to cover a shorter distance for reaching its objectivewhich more than compensates for the decreased speed as a result of theincreased coefficient friction.

I claim:

1. Rudder or keel for a wind and/or power propelled vessel,characterized in that the rudder or keel at its rear part has mountedthereon at least one extension blade which is adapted, from the hull ofthe vessel, to be rearwardly extended from and retracted to a positionwherein its rear edge substantially does not project rearwardly of thetrailing edge of the rudder or keel.

2. Rudder or keel according to claim 1 in the form of a hollow body withasymmetrically streamlined crosssection, characterized in that bothsides of the hollow body have provided thereon an extension blade whichin its retracted position closely seats on the outer surface of the saidbody.

3. Rudder or keel according to claim 2, characterized in that eachextension blade is secured to the hollow body by means of at least onebracket projecting into that body through a longitudinal slot in thewall thereof which bracket(s) or one of which brackets is or are actedon by operating means.

4. Rudder or keel according to claim 3, characterized in that eachextension blade has two vertically spaced brackets which carry a pinionat their inner end, said pinions being secured to a common rotary shaftextending perpendicularly to said longitudinal slot and each ride on atoothed rack secured on the inner side of the concerning wall when theextension blade is extended and retracted.

5. Rudder or keel according to claim 4, characterized in that thecontrol means each consist of a piston rod of a hydraulic ram securedinside the hollow body.

6. Rudder or keel according to claim 5, characterized in that thefore-end of each hydraulic ram and the rear-end of each piston rodhinges about a hinge pin extending parallel to the pinion shaft in thefront of the cavity of the hollow body and on the concerning bracketrespectively.

7. A wind and/or power propelled vessel fitted with a rudder and/or keelaccording to claim 1.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,690,284 Dated September 12 1972 Inventor) 1 Er icus Gerhardus Van DeStadt It is certified that error appears in the above-identified patentand that said Letters Patent are hereby corrected as shown below:

On the cover sheet [73] "Van de. Stadt, E Gr Scheepwert N V." shouldread E. G. Van de Stadt Scheepwerf N. V..

Also on the cover sheet, insert [30] Foreign Application Priority DataApril 16, 1970 Netherlands 7005497 Signed and sealed-this 20th day ofMarch 1973.

(SEAL) Attest;

EDWARD MFLETCHERJR. ROBERT GOTTSCHALK Attestin Offi I Commissioner ofPatents ORM DO-1050 H069) USCOMM-DC moan-ps9 U.$. GOVERNMENT PRINYINGOFFICE. I969 0-365'J34.

1. Rudder or keel for a wind and/or power propelled vessel, characterized in that the rudder or keel at its rear part has mounted thereon at least one extension blade which is adapted, from the hull of the vessel, to be rearwardly extended from and retracted to a position wherein its rear edge substantially does not project rearwardly of the trailing edge of the rudder or keel.
 2. Rudder or keel according to claim 1 in the form of a hollow body with a symmetrically streamlined cross-section, characterized in that both sides of the hollow body have provided thereon an extension blade which in its retracted position closely seats on the outer surface of the said body.
 3. Rudder or keel according to claim 2, characterized in that each extension blade is secured to the hollow body by means of at least one bracket projecting into that body through a longitudinal slot in the wall thereof which bracket(s) or one of which brackets is or are acted on by operating means.
 4. Rudder or keel according to claim 3, characterized in that each extension blade has two vertically spaced brackets which carry a pinion at their inner end, said pinions being secured to a common rotary shaft extending perpendicularly to said longitudinal slot and each ride on a toothed rack secured on the inner side of the concerning wall when the extension blade is extended and retracted.
 5. Rudder or keel according to claim 4, characterized in that the control means each consist of a piston rod of a hydraulic ram secured inside the hollow body.
 6. Rudder or keel according to claim 5, characterized in that the fore-end of each hydraulic ram and the rear-end of each piston rod hinges about a hinge pin extending parallel to the pinion shaft in the front of the cavity of the hollow body and on the concerning bracket respectively.
 7. A wind and/or power propelled vessel fitted with a rudder and/or keel according to claim
 1. 